Why Does Too Much or Too Little Sleep Cause Weight Gain?
The physiological functions of virtually all organisms are governed by 24-hour circadian rhythms. Your circadian clock is an essential time-tracking system, which your body uses to anticipate environmental changes and adapt to the appropriate time of day. Your circadian rhythm has evolved over hundreds of generations to align your physiology with your environment, and your body clock assumes that like your ancestors, you sleep at night and stay awake during daylight hours. If you confuse the situation by depriving yourself of enough hours of sleep, or even eating meals at odd hours (times at which your internal clock expects you to be sleeping), you send conflicting signals to your body. One way this occurs is by altering levels of important hormones linked with appetite and eating behavior. When you are sleep deprived, your body decreases production of leptin, the hormone that tells your brain there is no need for more food. At the same time it increases levels of ghrelin, a hormone t
